need help from you 1/4 gurus
#1
Super Member
Thread Starter
Join Date: Dec 2005
Posts: 975
Likes: 0
Received 0 Likes
on
0 Posts
SL65 AMG
need help from you 1/4 gurus
Does this go for the 65 motor as well? I have talked to a few guys that swear the higher oct helps the turbo cars. I ran a whold tank of 101 then went to the track and ran a 12.3@118 with a 2.05 60ft and last time I ran given I had my 100lb wife in the car and maybe another 6 gallons of fuel we ran a 12.6@114 with a 2.119 60ft? Given these times are for 5500ft. Any reason on the increase in speed other then the gas? Also I was hot lapping the car pretty bad with no rest, I would run drive up pit road then line up and race again and my time just kept dropping and dropping and I even was able to get a 1.9 60ft but my time was only a 12.4 @ 117 or 116, my last run was the fastest? (sorry this is from another post but you get the idea)
I ran trick 101 for an entire tank say 240 miles from city driving to wot runs to 60 to highway driving. I didnt feel an difference and was wondering if I just wasted money but the numbers say different. you figure with the gas and wife I lost maybe 150lbs and I am guessing about 6 gallons at 8lbs per gallon. My 60ft didnt get any better either so who knows. I have my gas light on now and I am planning on running 1 more time this sunday, not sure if I should get more 101 or just add the 91 from the pump?
I ran trick 101 for an entire tank say 240 miles from city driving to wot runs to 60 to highway driving. I didnt feel an difference and was wondering if I just wasted money but the numbers say different. you figure with the gas and wife I lost maybe 150lbs and I am guessing about 6 gallons at 8lbs per gallon. My 60ft didnt get any better either so who knows. I have my gas light on now and I am planning on running 1 more time this sunday, not sure if I should get more 101 or just add the 91 from the pump?
#3
Super Member
Thread Starter
Join Date: Dec 2005
Posts: 975
Likes: 0
Received 0 Likes
on
0 Posts
SL65 AMG
no, all the drag racers seem to be in the e55 forum. I was talking with the guys about octane booster and started going off on my 101 and my 1/4 times so just started a new thread so I wouldnt hi jack theirs. I have been told the ecu's will adapt. I even talked to brabus about the tuning they offer for the 65 and they said they do not tune for one octane but the ecu will learn the fuel and give me more power with higher octane is this true or is this
![bs](https://mbworld.org/forums/images/smilies/bs.gif)
#4
MBWorld Fanatic!
Join Date: Mar 2002
Location: South Florida
Posts: 1,662
Likes: 0
Received 1 Like
on
1 Post
STS,FGT,12C,P85D,M4
I've used the 101 gas from the track and didn't notice a difference.... weight will always slow you down, 100 pounds does make a difference.... try running with < 1/4 tank of gas and no passengers and see how it goes....
the weather and altitude are also big factors.... 5,500 feet is pretty high, if you were at sea level you could expect an extra 4MPH on those traps.... your ET's are all about your launch....
the weather and altitude are also big factors.... 5,500 feet is pretty high, if you were at sea level you could expect an extra 4MPH on those traps.... your ET's are all about your launch....
#5
MBWorld Fanatic!
Join Date: Jan 2004
Location: Salt Lake City (but not Morm)
Posts: 7,092
Likes: 0
Received 12 Likes
on
10 Posts
2003 E55 & 2014 GL550
When I get some time I am going to do a before and after dyno to finally put this to rest.
Course it will put it to rest for the supercharged cars, but the turbo mystery will remain I guess.
Course it will put it to rest for the supercharged cars, but the turbo mystery will remain I guess.
#6
MBWorld Fanatic!
no, all the drag racers seem to be in the e55 forum. I was talking with the guys about octane booster and started going off on my 101 and my 1/4 times so just started a new thread so I wouldnt hi jack theirs. I have been told the ecu's will adapt. I even talked to brabus about the tuning they offer for the 65 and they said they do not tune for one octane but the ecu will learn the fuel and give me more power with higher octane is this true or is this ![bs](https://mbworld.org/forums/images/smilies/bs.gif)
![bs](https://mbworld.org/forums/images/smilies/bs.gif)
It's BS. There is no way the computer can "learn" what octane you're using.
Generally speaking, you'll have a target advance in the computer and it will run that timing unless it senses a knock event. As the knock sensors detect the knock event, it will retard the timing according to the "attack" rate built into the computer and advance the timing back based on the "decay" rate.
If it senses a lot of events, it may go into a limp mode where it's running a reduced timing map, assuming the car has been filled with a lower octane fuel or has some other issue causing the knock events.
There is no way for the computer to know what's in the tank, it relies on tables in the ECU and the knock sensor to determine what's happening.
Cars in the US would be tuned for 91-93 octane, otherwise you'd constantly be experiencing knock as it tried to advance the timing for those rare times when you might put in race gas. While knock sensors are good for protecting engines, remember that they are reactive. The event has already occurred and the ECU is reacting to prevent future events by retarding the timing.
#7
Member
Join Date: Jun 2006
Location: Bay Area, CA
Posts: 233
Likes: 0
Received 0 Likes
on
0 Posts
E55
On my camaro with back to back dyno, without changing the timing, adding higher octane did nothing on the dyno. When I took it to the track, I still add higher octane if I can to increase my level of safety. For some who need to push the car to the limit, they will increase the timing to the max hp and add the require higher octane fuel to prevent detonation.
Therefore from my experience and my reading, if your car is not tune to need or require the higher octane fuel then you don't need it and it will be a waste of money.
Therefore from my experience and my reading, if your car is not tune to need or require the higher octane fuel then you don't need it and it will be a waste of money.